High Prevalence Of ESBL-Producing And Multidrug-Resistant Escherichia Coli In Urinary Tract Infections

Abstract

Background: Urinary tract infections (UTIs) are predominantly caused by Escherichia coli, with the rising prevalence of extended-spectrum β-lactamase (ESBL) production posing a critical challenge to effective therapy. Antimicrobial resistance (AMR) not only limits therapeutic options but also contributes to treatment failure and recurrence.

Objectives: This study aimed to (i) determine the prevalence of ESBL-producing E. coli isolates from urinary samples, (ii) evaluate phenotypic methods for carbapenemase detection, and (iii) assess antimicrobial susceptibility patterns, with a focus on multidrug-resistant (MDR) and extensively drug-resistant (XDR) profiles.

Methods: A cross-sectional study was conducted on 100 urinary E. coli isolates collected from catheterized patients with symptomatic UTIs between June 2023 and May 2024. Antimicrobial susceptibility was determined by Kirby–Bauer disc diffusion, interpreted according to CLSI (2023) guidelines. ESBL production was confirmed using the combined disc method, while carbapenemase activity was evaluated using the modified carbapenem inactivation method (mCIM) and EDTA-modified carbapenem inactivation method (eCIM).

Results: ESBL production was detected in 79% of isolates. MDR and XDR were observed in 60% and 18% of isolates, respectively, while 22% remained non-MDR. High resistance was noted against ampicillin (77.3%), cefotaxime (77%), cefixime (65%), and ciprofloxacin (60%). In contrast, fosfomycin (97.3%), gentamicin (96%), amikacin (80%), and imipenem (85%) retained good activity. Phenotypic carbapenemase assays demonstrated utility in differentiating serine-carbapenemases from metallo-β-lactamases.

Conclusion: The study revealed an alarmingly high prevalence of ESBL and MDR/XDR E. coli compared with regional reports. Fosfomycin, aminoglycosides, nitrofurantoin, and carbapenems remain effective agents, whereas cephalosporins and fluoroquinolones show limited utility. Continuous surveillance and antimicrobial stewardship are essential to prevent the emergence of carbapenem-resistant Enterobacteriaceae.